The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: email@example.com (Bill Sloman)
Subject: Re: Cheap low frequency impedance bridge?
Date: 13 Oct 2002 14:28:10 -0700
References: <3DA6E7D6.firstname.lastname@example.org> <email@example.com>
NNTP-Posting-Date: 13 Oct 2002 21:28:11 GMT
Winfield Hill wrote in message news:...
> Bill Sloman wrote...
> > The Analog Devices AD9854 DDS chip that produces tightly coupled
> > in-phase and quadrature outputs
> > http://products.analog.com/products/info.asp?product=AD9854
> > is exactly what I'd love to be able to use - much neater (though
> > probably no more effective) than the scheme Win Hill set around
> > two AD DDS chips.
> Check again Bill, my design uses multipliers, not DDS chips.
> [ big snip ]
> > I might even be able to sneak a precision ratio transformer (as
> > described in Rayner and Kibble) into the design.
> Highly appropriate for 0.1ppm designs, as mine was, but not for
> much lesser-resolution applications I'd think. But OK, for higher
> resolutions than say 20 or 50ppm, go for a ratio transformer. My
> design works well with or without one...
I've got some ideas for a cheap ratio transformer. According to Rayner
and Kibble, multi-tapped ratio transformers can offer 0.1ppm precision
and stability, but this doesn't preclude their use in less demanding
I've finally got myself a copy of H.K.P. Neubert's "Instrument
Transducers" OUP(1963) and he is nuts about (Blumlein) transformer
bridges, pretty much as I remember from reading the book in the
Melbourne University physics library, shortly after it was published.
Getting winding ratios that are accurate as well as stable is just
icing on the cake.
Bill Sloman, Nijmegen
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup